checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
        "https://checkstyle.org/dtds/configuration_1_3.dtd">

<module name="Checker">
    <property name="charset" value="UTF-8"/>

    <module name="TreeWalker">
        <!-- Ensures that the outer type file name matches the type name -->
        <module name="OuterTypeFilename"/>
        <!-- Checks for any unused imports in the Java source code -->
        <module name="UnusedImports"/>
        <!-- Check for method names check of camel case-->
        <module name="MethodName">
            <property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
        </module>
        <!-- local variable names check of camel case -->
        <module name="LocalVariableName">
            <property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
        </module>
    </module>
</module>